update changelog

Author: Conduitry

CHANGELOG.md

@@ -3,6 +3,7 @@
 ## Unreleased
 
 * Fix misaligned line numbers in source maps ([#3906](https://github.com/sveltejs/svelte/issues/3906))
+* Make setting a `tweened` store using `duration: 0` instantly update the value ([#4399](https://github.com/sveltejs/svelte/issues/4399))
 * Fix reactivity with imported values that are then mutated ([#4555](https://github.com/sveltejs/svelte/issues/4555))
 * Do not display a11y warning about missing `href` for `<a>` with `name` or `id` ([#4697](https://github.com/sveltejs/svelte/issues/4697))
 * Disable infinite loop guard inside generators ([#4698](https://github.com/sveltejs/svelte/issues/4698))